To check terns, as well as MeSH there is now a Metathesaurus from UMLS (developed in conjunction with the US National Library of Medicine). The Metathesaurus is mapped against MeSH and contains ‘information about biomedical concepts and terms from many controlled vocabularies and classifications used in patient records, administrative health data, bibliographic and full-text databases, and expert systems’. It can be particularly useful for checking out non-MeSH terms – i.e. synonyms. The Metathasaurus also maps terms in languages other than English (this can be useful if you wanted to conduct a ‘words anywhere’ search using non-English terms.
To see the Metathasaurus, go to: http://umlsks.nlm.nih.gov/kss/servlet/Turbine/action/KssLogin Registration is free.